Photographic elements bearing silver halide emulsion layer and adjacent light-insensitive colloid layer containing silver derivatives of azoles



DCC- 16, 1947. 1 w. H. DIMSDALE ET Al. 2,432,864

PHOTOGRAPHIC ELEMENTS BEARING SILVER HALIDE EMULSION LAYER AND ADJACENTLIGHT-INSENSITIVE COLLOID LAYER CONTAINING SILVER DERIVATIVES OF AZOLESF11-ed Jan. 1a, 1945 v 'F/azj SILVER DERIVATIVES OFSULFUR-AZ SILVERHALIDE EMULSION LAYER FILM SUPPORT SILVER HALIDE EMULSION LAYERWATER-PERMEABLE COLLOID LAYER CONTAINING SILVER DERIVATIVES OFSULFUR'AZOLES FILM SUPPORT SILVER HALIDE EMULSION LAYER WATER-PERMEABLEGOLLOID LAYER CONTAINING SILVER DERIVATIVES OF SULFUR'AZOLES SILVERHALIDE EMULSION LAYER FILM SUPPORT y r I I SILVER HALIDE EMULSION LAYERFILM SUPPORT WATER-PERMEABLE GOLLOID LAYER CONTAINING SILVER DERIVATIVES0F SULEURAZOLES INVENTORS W/LFR/D HAM/DEN D/MSDALE ggd R/OHA no Roa En rRoem/50N' A TTOPJI/E Y Patented Dec. 16, 1947 'PHOTOGRAPHIC ELEMENTSBEARING SIL- `VER HALIDE EMULSION LAYER AND AD- JACENT LIGHT-INSENSITIVEHCOLLQID LAYER CONTAINING TIYES OF AZOLES SILVER DERIVA- `WilfridHampden Dimsdale and Richard VRobert Robinson, Ilford, England,assignors to Ilford Limited, Ilford, England, aritish companyApplication January 18, 1945,:Se1'ial No. 573,460 In Great BritainFebruary 3, 1944 5 Claims.

This invention relates-to photographic lightsensitive elements,toco-mpounds which serve as improvers for photographic sil-ver halideemulsions, and particularly to compounds which improve the quality ofthe developed photographic images obtained in such emulsions.

In the production ofphotographic .images in silver halide emulsions, andparticularly in the case of emulsions consisting primarily of silverchloride, the maximum image density obtainable is not always so great asmay be desired. Moreover,'the .common practice of hot-glazingphotographic prints tends to affect adversely the image colour, giving apoor quality black which has a bronzed appearance, and also reduces theeffective maximum density obtainable Yin the image.

In British Patent No. 561,875 methods are` described for improving thequality of -the developed photographic images which comprise treatingthe emulsions With 5-'mercapto tetraz`oles.`

These compounds may be introduced into `the emulsion itself, or into asubcoat, supercoat or backing A.layer,'or 'they may be'included in theWrapping materials used. Alternatively, the compounds may be applied 'in`solution fto 'the emulsion before or during development, e. g. byincluding them 'in the developing solution used. These compounds, isoused, .not l'only improve the maximum image density obtainableand serveas anti-bronzing agents, but also reduce the level `of fogintheAdevelopedimage. As stated in the said patent,`- compounds used toreduce the fog level'frequently cause a serious reduction in the speedof the -emulsion, and it is an advantage of the Ycompounds .describedinthe said patent that `the reduction ,'inspeed whichthey cause .is notserious. Nevertheless, .in'the case of many Lof :the compounds,v 'some'reduction in nspeed is caused by their use, as indicated by the figuresset out in Table I of the said patent.

There are other classes of compounds which serve to increase the maximumimage density obtainable and serve as anti-bronzing agentsamong whichare -mercapto-1.2.4-triazoles described .in U. SxapplioationNo. 553,270.These compounds, Wheni'incorporatedin `the emulsion `or, `developer alsoserve to 'decrease the fog level in the. developed image, and also'sometimes effect a decrease inthe 'speed l`of the emulsions.

Whilst the method 'ofusing such compounds jdescribed in the `said 111;S. application Serial No.

558,270, filed October 11, 1944, ydoes not lead to a loss in speed ofthe emulsion, since thecompounds are not. applied, until' the emulsionhas alreadybeen developed, thefmethod entails that the user needs toemploy special fixing, `,glaz/:ing orothersolutions containing thecompounds, It would ,clearly be an advantage for the manufacturer-.to beable to include Jthe `compoundin the photosensitive element as`marketed, providing thatits presence in such element didnotunduly reducethe speed of thephoto-sensitive emulsion.

.The .present invention is concerned With. a methodof including `thecompounds in the pho- Ato-sensitive .element itself .in a form such thatanytendency .for lthe compoundto reduce the speed ofthe photo-sensitiveemulsion .is reduced or -eliminated.

According to thisinvention there is` added to aphotographic emulsion `ortoa colloid medium other Ythan'the emulsion which forms avWaterperr-nealcle layer vin a photographic .element including a silverhalide .emulsion layer, a silver derivative of a `compound which, whenadded in itsfree state, or in the4 state of its alkalimetal derivative,improves the quality 'of photoygraphic. images developed in suchemulsion layers. L The term added is intended to mean `that the siiverderivative ,itself is added orthat reagents are added which reactamongthemselves to form the `silver derivative. The mere addition ofthe freecompound or of fits alkali-metal derivative to a silver. halide.emulsion with the consequent Vpossible formation of somesilverde-.rivaux/e by react-ion with part of the einerv ,of

the emulsion itself =is lnot included Withnthe meaning of the term anddoes not give the same results as are'obtained bythe process of thisinvention.

The term silver derivative is intendedto mean a derivative resultingfrom replacement of hydrogen `in the said compound by silver.

In a preferred form Yof the invention the silver derivatives are addedto colloid media which are to be used for coating layers in ContactWiththe silver halide emulsion layer or layers. For example, the silverderivative may be included in Aa supercoat layer, e. g., a colloidlayer-coated on top of the photographic emulsion layer and forming, forexample, anouter layer of the element, or may be .includedin asubcoatlayer, e. g., a colloid layer v lying between aphotographic'emulsion layer and a support layer, or may be included inan inter-layer between two emulsion layers. It may, however, be presentin other layers, for example a backing layer.

The pho-tographic elements described in the preceding paragraphs areillustrated in the accompanying drawing wherein:

Fig. 1 is a cross section of a film bearing a silver halide emulsionlayer` and a superposed layer containing an anti-bronzing agent of thetype described below;

Fig. 2 is a cross section of a similar lm wherein the silver halidelayer is outermost;

Fig. 3 is a cross section of a similar film wherein a colloid layercontaining an anti-bronzing agent is disposed between two emulsionlayers; and

Fig. 4 is a cross section of a modified lm wherein the two layers are onopposite surfaces.

Referring more particularly to the drawing, in Fig. 1 a iilm support lis provided with a silver halide emulsion layer 2 on which there isdisposed a water-permeable colloid layer 3 containing an anti-bronzingagent of the type disclosed below.

In Fig. 2 a lm support I is provided with a water-permeable colloidlayer 4 containing an anti-bronzing agent as herein disclosed on whichthere is disposed a silver halide emulsion layer 5.

The element of Fig. 3 consists of a nlm support I bearing silver halideemulsion layers 6 and 8. between which there is disposed awater-permeable colloid layer 'l containing an anti-bronzing agent asherein disclosed.'

The element of Fig. 4 consists of a lm support l bearing a silver halideemulsion layer 9 on one surface and having disposed on the other surfacea water-permeable eolloid layer l containing a herein disclosedanti-bronzing agent.

It is desirable, especially where the silver derivative is included in asupercoat or in the emulsion layer itself, that it should be in a veryfine state of subdivision in the layer in which it is incorporated.Thus, a convenient method of use is to form the silver derivative insitu in the colloid medium in which it is to be dispersed, for exampleby the double decomposition of a soluble silver salt and an alkali-metalderivative of the compound in a gelatin medium.

The invention may be applied to all varieties of compound which arecapable of improving the quality of the developed image and which willform silver derivatives.

The following are typical classes of compounds which may be used, astheir silver derivatives, in accordance with this invention.

(a) Compounds of the type described in British Patent No. 561,875. Theseare -mercapto tetrazoles and specific examples are:

1-phenyl-5-mercapto-tetrazole 1-a-naphthyl--mercapto-tetrazole1--naphthyl-5-mercapto-tetrazole 1-p-diethylaminophenyl-5-mercapto-tetrazole l-o-methoxy phenyl--mercapto tetrazolel-p-chlor phenyl-5-mercapto-tetrazole 1benzyl5-mercapto-tetrazole1-cyclohexyl-5-rnercapto-tetrazole 1-methy1-5-mercapto-tetrazole1-ethyl-5-mercapto-tetrazole (b) The -mercapto-1.2.4-triazoles describedin U. S. application Serial No. 558,270, referred to above. Specificexamples of these are:

1.2-dimethyl-5-mercapto-1.3.4-triazole1-ethyl-2-methyl-5-mercapto-1.3.4;-t1fazole1-phenyl-2-methy1-5-mercapto-1.3.4triazolel-phenyl-5-mercapto-1.3.4-triazole l-benzyl-S-mercapto-1.3.4-triazo1e 1-methyl-2-ethyl-5-mercapto- 1.3.4-triazole1-methyl-2-n-hexyl--mercapto-1.3.4-triazole l-p-hydroxyphenyl-2-methyl-5-mercapto-1.3.4-

triazole l-p-arnino phenyl-2-methyl-S-mercapto-1.3.4-

triazole 1a-naphthyl-2-phenyl-5-mercapto-1.3.4-triazole2-a-naphthyl-5-mercapto-1.3.4-triazole1.2-diphenyl-5-mercapto-1.3.4-triazo1e (c) Heterocyclic nitrogencompounds containing two nitrogen atoms in the ring and one, two orthree sulphur atoms attached to carbon atoms which are in fic-positionto the nitrogen atoms (compounds containing a single sulphur atom linkedto a carbon atom which is a to both nitrogen atoms are included but aregenerally less eflicient). Examples of this class of compound are:

2.5-dimercapto-1.3.4-thiodiazole 2-mercapto-5-amino-1.3.4-thiodiazole1-mercapto-4-hydroxy-phthalazine 1.4-dim-ercapto-phthalazine2.5-dimercapto-3-methyl-1.3.4-thiodiazole 2-hydroxy-4-mercaptopyrimidine 2 :4-dimercapto-pyrimidine 2 :4-dimercapto-quinazolineTrithio barbituric acid (d) Mercapto hydroxy diazoles, an example ofwhich is:

2-mercapto-4-phenyl-5-hydroXy1.3.4 thiodiazole.

(e) Dimercapto monazoles, an example of which is:

2.4-dimercapto quinoline.

(f) Mono mercapto monazoles, examples oi which are:

2-mercapto-benzthiazole 2-mercapto-benzoxazole 2-mercapto-quinoline2-mercapto-6-7-benzbenzthiazole (i. e., naphthathiazole)4-mercapto-quinoline.

EXAMPLE I 1 gram of 1-phenyl-2-methyl-5-mercapto- 1.3.4-triazole wasdissolved in 3.6 ccs. of a 40% aqueous solution of sodium carbonate(Cryst). This solution was added to 250 ccs. of a 4.4% solution ofgelatin (containing a small quantity of dispersing agent) and made up to500 ccs. with water. 77.7 ccs. of a 1% aqueous solution of silvernitrate was added to 250 ccs. of a 4.4% solution of gelatin (containinga small quantity of disture wascooledto'dorm afsrnall amountrofronn--Jal'd'ehyde a'd'ded and ttlfien, 1 after' stari'ding; was coated at 80F. asA afsupercoatr (fai afstandard silverfbromideemulsion-'asmsedi 'oraryfbro- Timide prlinting paper.Y 4"and T:Cb -a ta 'da-rdrsi-lverchloride Iemulsiorifasyusediirikordiriary ffooritact" Aor gas1ightprinting paper; ftheV ul'sion ilayers `being carried f onfpaper1-s',upp'cr-ts. Testfsaniples `of the fdriedfcoatings were4exposedrbehindaidensity rstep wedge,` developed and xfed. :'JSomeIsamples Wereidried normally ramd othersilwere dried on -alcommerc'ialhotiglazin'g machine.

'Control samples, 'in fwhi'ch the triazole voorn- :p'oundfwas LomittedVfrom @the gelation "superooat, -were similarly processedaand'tne speedandimanimum image density (Dmax) Were determinedior FtheI.various1samples. The fre's'ultslobtained were .fassetrout1in-.the`following" Tabler:

vTable .Y

.randltheereslts.nbtainedfwere .fasssettoufzfixtzthe sesSilverBroinidCoatings4 `Si1verChlorldlGoatings following Table II:

AZThese speed values 'are calculatedas before. Again "there is nomeasurable' loss in Jspee'din vfthe jcaseof the silver chlorideemulsiorrcoatingsj'b'ut there is `some loss in-thecase'of the silverbromide emulsion coatings. MHowever,l a comparable test on the silverbromide material =using Ja superco'a't containing the freecompound(i."'e.,riot"'asithe Asilverderivati-ve) sh'ovved "a speed valueonly-T5 lof* that of 'the 'test "sample o'f the above Table"'[I. 'Thetestsamples `in all cases vshowed* 4a markedly llessdegree of bronzingAafter hot-glazing, `than "the "control *rt-should 1'tepointedout-therme speed' vfigures given V:in this "example `are not'comparable with 1130 I "PatenNo': 561;'8'75. `thoughthe ysame"compoundis `in use; "for the reason that 4Vin I'the' present 'case very muchlarger quantities of the compound have Ebeent'aken in ythe' examples-and'the-fernulsionsl used are different.

11i-EXAMPLE rIII 'free generar procedure- Forex-amples'"nano 1111Vwas"followed using concentrations-oi 1-`partfdf Vthe@silver-derivative! "in- 50'00 Cparte f'i fthe fge tin Ksincerco'atsolution, |other compounds' than Table `III .'Slver Broniide CoatingsVSilver Chloride .Coatings i.

AD normallyJ ""Dvm hot- "l 'Dm normally r"D hot- Compound mariee gled"d1-ieu lzed Control Test Control Test Control Test Control Test2.4-di-me1capto pyrimidine 1. 91 1.94 1. 70 2.05 1. 74 1.86 1. 46 2.001-mercapto-4-hyd10xypl1thalazne l. 83 1. 94 1. 58 1. 99 1. 75 l. 90 l.45 l. 98 Z-mercapto-benzthiazole 1.83 1.89 1. 58 1. 94 1. 75 1. 86 1.45 1. 97 2.4.dimercapt0 quinoline 1.82 1.85 1.71 1.90 1.80 1.83 1.531.86

parable test on the silver bromide material using a supercoat containingthe free compound (i. e., not as the silver derivative) showed a speedvalue only 1% of the speed of the test sample of the above Table I. `Thetest samples in all cases showed a markedly less degree of bronzng afterhot-glazing than the control.

EXAMPLE II The procedure given in Example I Was followed with thevariations that the compound used Was l-phenyl--mercapto-tetrazole, itwas dissolved in 5.0 ccs. of the sodium carbonate solution and thequantity of silver nitrate solution taken was 95.5 ccs. All otherconditions remained the same EXAMPLE IV The silver derivative oflr-phenyl--mercapto tetrazole was prepared and added in finely dividedcondition to silver chloride and silver bromide emulsions, one part ofthe silver derivative being added per 1000 parts of emulsion. Tests weremade as before and gave the results set out in Table IV.

The bronzed effect of the control samples, shown particularly on thehot-glazed samples, was substantially eliminated in the test samplesand, though some loss in speed Was caused by the addition of the silverderivativeto the bromide emulsion, this loss was less than is caused bythe addition of the free compound. An increase inv Dmax was effected inall cases.

What we claim is:

1. A photographic element comprising a silver halide emulsion layer and,in Contact therewith,

a Water-permeable light-insensitive colloid layerl which contains asilver derivative of a compound selected from the class consisting of-mercaptotetrazoles, -mercapto-1.3.4-triazoles, diazoles containing upto three sulphur atoms attached to carbon atoms which are in a-positionsto the cyclic nitrogen atoms, mercapto hydroxy diazoles, dimercaptomonazoles and monomercapto monazoles.

2. A photographic element comprising a silver halide emulsion layer andan outer water-permeable light-insensitive colloid layer in contact withsaidemulsion layer, said outer layer containing a preformed silverderivative of a compound selected from the class consisting of 5-mercapto-tetrazoles, 5 mercapto-1.3.4-triazoles, diazoles containing upto three sulphur atoms attached to carbon atoms which are inaL-positions to the cyclic nitrogen atoms, mercapto hydroxy diazoles,dimercapto monazoles and mono mercapto monazoles.

3. A photographic element comprising a silverhalide emulsion layer ofwhich the predominant silver halide is silvei` chloride and, in contacttherewith, a water-permeable light-insensitive colloid layer whichcontains a silver derivative of a compound selected from the classconsisting of -mercapto tetrazoles, 5 mercapto 1.3.4-triazoles, diazolescontaining up to three sulphur atoms attached to carbon atoms which arein a-positionsvto the cyclic nitrogen atoms, mercapto hydroxy diazoles,dimercapto monazoles and mono mercapto monazoles.

4. A photographic element comprising a silver halide emulsion layer ofWhich the predominant silver halide is silver chloride and an outerwaterpermeable light-insensitive cclloid layer in contact with saidemulsion layer, said outer layer containing a silver derivative of acompound selected frum the class consisting of 5-mercaptotetrazoles,5-mercapto-1.3.4triazoles, diazoles containing up to three sulphur atomsattached to carbon atoms which are in na-positions to the cyclicnitrogen atoms, mercapto hydroxy diazoles, dimercapto monazoles and monomercapto monazoles.

5. A photographic element comprising a paper support carrying a silverhalide emulsion layer and an outer Water-permeable light-insensitivecolloid layer in Contact with said emulsion layer, said outer layercontaining a silver derivative of a compound selected from the classconsisting of 5-mercapto-tetrazoles, 5-rnercapto-1.3.4triazoles,diazoles containing up to three sulphur atoms attached to carbon atomswhich are in a-positions to the cyclic nitrogen atoms, mercapto hydroxydiazoles, dimercapto monazoles and mono mercapto monazoles.

WILFRID HAMPDEN DIMSDALE. RICHARD ROBERT ROBINSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,057,764 Brunken Oct. 20, 19362,066,099 Dieterle Dec. 29, 1936 2,221,805 Leermakers Nov. 19, 19402,377,375 Russell June 5, 1945 FOREIGN PATENTS Number Country Date390,037 Great Britain Mar. 30, 1933

